Treatment of metal surfaces



Patented June 5, 1928.

UNITED STTES PATENT METAL COMPANY, LIMITED, LONDON, ENGLAND.

TBEATMEN T 01 METALSULRFAGES.

No Drawing. Application filed March 3, 1927, Serial No. 172,565, and in Great Britain March 17, 1928.

Many metals when heated to a high temperature when exposed to the atmosphere become corroded.

This invention relates to a process for 6 treating metal surfaces, whereby the article or object treated does not become corroded when heated to a high temperature or become less liable to corrosion.

According to this invention metal articles 10 or objects are given a coating of the sulphide of the metal in question through the action of carbon disulphide on the heated article or object.

As the metallic sulphide is formed by the action of the carbon disulphide vapour upon the oxide of the metal, the surface of the article treated is. if necessary, before treatment with the carbon disulphide, given a thin firmly adherent film such as can be obtained usually by heating in the presence of air.

As an example of treating steel articles are packed in a closed container so that any vapour or air can have free access to the surface to be treated. The container has an inlet for air and an inlet for carbon disulphide vapour.

The articles are, if not having a film of oxide, subjected when at a temperature of above 600 C. to the action of air for a few seconds. Carbon disulphide is Down/admitted at, say a pressure of 4 lbs, for about ten minutes, while the articles are at a temperature of. say, 700 C.

The invention is particularly applicable for aluminum and magnesium and metals coated therewith.

What 1 claim is 1. A process for treating a metal surface so as to protect the basic metal from corrosion which consists in subjecting the metal surface whilst in an oxidized state to the action of carbon disulphide whereby a coating of the sulphide of the basic metal is produced.

2. A process for treating a. metal surface so as to protect. the basic metal from corrosion which consists in exposing the metal to oxidizing conditions to produce a film of oxide at the surface and then subjecting the oxidized surface at an elevated temperature I to the action of carbon disulphide.

3. A process for treating a metal surface so as to protect the basic metal from corrosion which consists in subjecting the metal surface at an elevated temperature firstlyto the action of air and then to the action of carbon disulphide.

In testimony that I claim the foregoing as my invention I have signed my name this 16th day of February. 1927.

WALTER SMITH. 

